Ore-roasting furnace.



v PATENTED SEPT. 18, 1906. W. A. MADDBRN. ORE ROASTING FURNACE.

ill/A APPLICATION FILED APR. 7, 1903.

IIIIIIIIIIII/I/fi In THE NORRIS PETERS ca., wasmmzmrl, n c.

I WILLIAM ALEXANDER MADDERN, OF BOULDER CITY,

WESTERN AUS TRALIA, AUSTRALIA.

ORE-ROASTING FURNACE.

Specification of Letters Patent.

Patented Sept. 18, 1906.

Application fil d April '7, 1903. Serial No. 151,542.

To all whom it may concern:

Be it known that 1, WILLIAM ALEXANDER MADDERN, engineer, a subject of His Majesty King Edward VII, residing at Boulder City, in the State of Western Australia, Australia, have invented Improvements in Ore-Roasting Furnaces, of which the following is a specification.

My invention relates to improvements in ore-roasting furnaces, the special object of the same being to construct and arrange the several parts so as to render the appliance applicable to the economic roasting of tellu-' ride ore, arsenical pyrites, or any other class of ore, special attention being given to the conservation of heat at all points in reducing radiation, subjecting the ore to a graduallyincreasing heat, subsequently extracting the heat from the roasted ore by passing atmos pheric air over the same, and utilizing the thus heated air for combustion in thegrate, and in further drawing from this hot-air supply through holes in the fire-bridge for completing the combustion of unburned gases or carbons.

The furnace used for the purpose indicated may have one or any number of superimposed hearths which are mechanically rabbled. With a furnace constructed according to my invention heated air can also be admitted for oxidizing effects at any points in the furnace by using an air-cooled rabble. Moreover, special attention is directed to the reducing-gear, which is made with as few working parts as possible, so that very little friction is caused in applying the same. 7 An important feature in my invention lies in the fact that all parts are readily accessible for inspection and repair, and the rabbles, which are connected with vertical spindles, are specially positioned at the side of the furnace, so that being in comparatively cool air they can readily be uncoupled, withdrawn, or replaced by new ones with the least possible loss of time.

The construction of the furnace is such that the ore is continually stirred throughout the whole width of the hearth, fresh faces being exposed at each forward and backward sweep of the rabble, thus insuring direct contact of the whole mass with the desulfurizing and oxidizing agents in the furnace.

In order that my invention may be the better understood both as regardsconstruction shaft, showing the rabblejoint.

and methods of operation, I will now proceed to describe the same by the aid of the accompanying illustrations, wherein- Figure 1 is a longitudinal section through the furnace. Fig. 2 is a horizontal section of the furnace. Fig. 3 is a transverse section through the furnace. Fig. 4 is an elevation of the sliding sleeve on the vertical square Fig. 5 is a part section and elevation of the air-cooled rabble, toggle-joint, and sliding sleeve. Flg. 6 is a section of the toggle-joint. Fig. 7 is a plan of the bottom socket of the toggle-joint. Fig. 8 is a section of the water-cooled rabble. Fig. 9 is a section of the watercooled rabble, showing inlet and outlet water-pipes. F g. 10 is a plan of the air-cooled rabble and sliding sleeve.

Throughout the drawings similar letters of reference are used to denote corresponding parts wherever they occur.

In this respect A is a feed-chute through which ore is admitted from a suitable feeder and is passed onto the top hearth B and is then rabbled along it to the discharge-hole A, from whence it is taken along the finish ing-hearth B to the discharge-hole A and onto the cooling and regenerating hearth B It is further rabbled throughout this length, thus losing its heat in imparting it tothe in coming air required for combustion of the fuel, and is finally delivered as finished product to the conveyer O by a discharge-apron A The fire-box is shown at D and is arranged to draw its hot-air supply from the regenerative hearth B through the passages E E Air at atmospheric temperature may also be supplied partially or wholly by opening the ash-door under grate. The hot gases sweep over hearth B to the flue F, which may lead from top or bottom of the furnace in any desired direction of heat from the hottest part namely, along the crown of hearth;B is utilized by conduction in the top hearth. Further radiation therefrom is prevented by a layer of sand or other suitable non-conducting material, as shown. Cold air is prevented from entering at the rabble-arm slots by a curved plate 00, attached to the arms and working with the same close to the cast-iron pocket S, so as to keep the slot always covered. These cover plates or shields may be made of light steel a cooled and framing covered with woven asbestos fixed on with copper rivets and attached in such a way that it may be easily replaced when worn out or destroyed.

The rabbling of the ore is effected by the use of semirotating arms of any section which have blades or plows H attached on under side, set at an angle so as to turn the ore over on both forward and backward strokes. A toggle having barrel-shaped ends working in suitable sockets is loosely attached by a light bolt to the rabble and is so arranged that during the forward stroke it hangs free in'the open core of the bottom socket J, and thus allows the rabble-arm to swing on the level or horizontal plane, as fixed by the collar L or vertical shaft I. 011 the backward stroke the toggle engages with the bottom socket and hinging therein slowly raises the rabble-arm to a height regu lated to the requirements of the tonnage by the height of the collar L on vertical shaft I. It then slowly lowers said rabble, which thus describes an arc, and by a further onward movement is drawn out of its socket into the open core. Thus an amount of ore regulated at will is taken along at each forward stroke. A water cooled rabble is shown in detail at H, the water entering in at pipe M and passing out through pipe N, each pipe being connected by hose to a downpipe placed in any convenient position. An air-cooled rabble is also shown at H. The cold air is admitted through a central slot and passes out through the holes at end, as indicated by the arrows. The rabble arms are attached to the long sliding sleeve K by means of a circular end fitting a hollow split boss and securely gripped. therein by a strong through-bolt. The collar L is in halves and can be made of any thickness to suit the amount of lift required. It is securely clamped to the central square shaft I over an octagonal or round neck formed on same. The heavy sleeve K is free to slide upward when raised by the toggle J and all side thrusts are obviated by the said toggle being placed under the center of gravity of the weight of rabble and sleeve; The sockets J and J 2 are shown in their relative positions. The square shaft I turns in two bearings, the bottom being a foot-step, and are driven by wrought iron or steel levers O, the whole being connected by steel rods P I in a parallel motion to the connecting-rod Q, which is driven from a crank-pin placed in the strong crown-wheel R. Suitable gear for, reducing speed can be supplied as desired. In the arrangeme'nt shown two sets of rabbles balance each other, since the lift of one set corresponds to the lowering of the other. Thus the thrust on the rods is only that necessary to raise the cooling-floor rabbles, (added to the ore resistance) which can be ofv very light section.

For the economic working of my invention I find that a speed of about two strokes per minute gives a satisfactory resultwith a lift of one inch; but a slight increase in lift Will nearly double the output.

The furnace is lined with brick, good firebrick being preferred for fire-box and middle hearth, as shown in cross-section lines, and is to be bound securely by T-irons and L-irons tied to stiff buckstays by tie-rodsand nuts.

What I do claim as my invention, anddesire to secure by Letters Patent, is

1. In improvements in ore-roasting furnaces a series of blades or plows mounted 'upon, and in combination with a semirotatmg arm, said blades or plows being set in series at opposite angles for the purpose of turning the ore over on both forward and backward strokes, substantially as described and illustrated in the accompanying drawin s.

2. In improvements in ore-roasting furnaces a se'mirotating rabble-arm provided with blades or plows for turning the ore, said rabble being arranged in combination with mechanism whereby it is raised for a portion of the back stroke so as to pass over the ore in the are of a circle but returns horizontally, thereby carrying more ore during the forward stroke than during the backward stroke, substantially as described and illustrated in the accompanying drawings.

3. In improvements in ore-roasting furnaces the combination of a rabble, a toggle having barrel-shaped ends, a bottom socket, a top socket and hinge as illustrated, arranged together for the purpose of allowing a rabble to be moved both horizontally and vertically for the purposes set forth and illustrated by the accompanyingdrawings.

In witness whereof I have hereunto set my hand in the presence of two witnesses.

WILLIAM ALEXANDER MADDERN.

Witnesses:

SAMUEL JEAvoUs, JAMES HOWARD HAYEs. 

